I have had this persisting problem for a bit now, I have completed all calibrations and when I go to arm it it successfully does it in APM Planner 2 but the motors do not start up, it just continues to beep. Any suggestions?
Some more details are required.
How have you got your ESC’s connected?
Does “continues to beep” refer to the ESC’s?
How are you arming it in APM Planner?
Are you using a radio?
What flight controller are you running?
What firmware?
Have you pressed the Safety Arming switch?
ESC’s are 80amp connected through a PDB, and the esc’s continue to beep despite mission planner saying that is armed, I’am arming it with the program and have also tried arming through my Horus X12s radio to no avail. I am running a pixhawk 2 and am thinking of reinstalling my pixhawk 1 am having the same issues. And yest I have armed the safety switch but either it continues to beep or only two motors will start.
Thanks for the reply 
Sounds like a signal to ESC problem.
How do you have the ESC’s signal wires hooked up?
Which wires from the ESC do you have plugged in?
Do the ESC’s have BEC’s and is the +ve lead plugged in?